The Torsatron TJ-K is a toroidal device operated with a magnetically confined low-temperature plasma to study turbulence and wave propagation. The magnetic configuration is the same as for a fusion plasma device. However, the plasma parameters are such that probes can be used in the entire plasma cross section to measure the detailed spatiotemporal structure of the turbulence. At the same time, the dimensionless parameters governing turbulence are in the same range as those of the fusion plasma edge. The objective of the experiment is to obtain data, which allow a close comparison with drift-wave turbulence simulations. Furthermore, the propagation of the helicon heating wave in a toroidal geometry as well as excited gap Alfvén modes will be studied. The article presents the experimental setup and the diagnostics. It is demonstrated that the TJ-K plasma has parameters and profiles relevant to achieve the objectives of the project. First results of turbulence and wave studies are presented.
Abstract. A toroidal low-temperature plasma is used for comparative turbulence studies. Measurements are carried out with Langmuir probe arrays in the entire plasma cross section. The data are closely compared with drift-Alfvén turbulence simulations. Although the parameters in a low-temperature plasma are very different from those in fusion plasmas, the dimensionless parameters governing the drift-wave physics are comparable. Hence this study can also give insight into high-temperature plasma turbulence. In order to identify relevant characteristic signatures of different turbulence-driving mechanisms, simulations were carried out for a wide range of plasma parameters. The simulation results are compared with first measurements.
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